This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 11-291342, filed Oct. 13, 1999, the entire contents of which are incorporated herein by reference.
The present invention relates to an electric substrate and a method for manufacturing a product using this electric substrate, and for example, to a flexible printed substrate for mounting in a camera.
In designing a flexible printed substrate, positioning holes must typically be formed which define the correct position relative to a mounter machine for mounting a predetermined electric part on the substrate. For example, when a mounter machine is used to mount a part such as a chip on a flexible printed substrate, which is to be assembled into a camera, at least a set of through-holes must be opened in the printed substrate at predetermined positions.
A set of small holes separated as far as possible are conventionally formed in a printed substrate with a circuit pattern design applied thereto, so as to be used for positioning for a mounter. For example, as disclosed in Jpn. Pat. Appln. KOKAI Publication No. 60-106751 for a technique for mounting an electric substrate, small holes in a flexible substrate are fitted over pins projected on a palette for positioning, and a mounting operation is then performed with this substrate held in tight contact with the palette in a vacuum.
These positioning holes in the substrate are desirably formed at positions that do not affect the arrangement of the circuit pattern, but the installation positions of the positioning holes have been easily determined fortunately because the circuit pattern arranged in the conventional printed substrate has a relatively low formation density.
Recent cameras composed of electronic devices, however, are smaller and have more advanced functions, so that the degree of freedom is substantially limited in mounting a flexible printed substrate assembled into the device. The density of the circuit pattern is also increasing to enhance the functions of the circuit, resulting in the need to further reduce a pattern width. No prior art documents, however, describe the above described problem with the positioning of the flexible printed substrate in detail.
One of the problems is that it is very difficult to find spaces on a flexible printed substrate in which positioning holes for a mounter machine are formed, the flexible printed substrate being designed to have a high-density pattern and that no positioning hole may be formed on the substrate depending on the relationship between the layout and pattern design of the printed substrate assembled into the camera main body.
Additionally, as shown in FIG. 4, particularly the shape of a flexible printed substrate 100 three-dimensionally assembled into a camera tends to be increasingly complicated as the camera becomes smaller and its functions become more advanced. Thus, the main printed substrate 100 main body has a large number of small substrates branching therefrom, so that it is difficult to keep the substrate two-dimensionally developed, thereby hindering the correct positioning relative to a mounter machine (not shown).
Furthermore, since a base of the printed circuit board 100 is made of a very thin film or the small substrates branch in every direction from the main body and are very flexible, a mounting area 20, 30, 40, 50, or 60 is relatively xe2x80x9ctwistedxe2x80x9d or xe2x80x9cpeeled offxe2x80x9d from a palette surface while parts are being mounted, thereby preventing maintenance of the planarity of the printed substrate 100 developed on the palette.
For the printed substrate 100 in FIG. 4, to avoid a high-density circuit pattern (not shown), for example, a semicircular recess 51 that is not fully circular are formed on the flexible printed circuit main body as a desperate measure, to temporarily form a set of positioning holes 51 and 61, which also serve to stop the printed circuit 100 from rotating.
As described above for the recent cases, the entire substrate is designed to have a slightly larger total area so that the positioning holes for the mounter machine do not affect high-density pattern sections or high-density part mounting sections of the circuit.
Preferably, however, the flexible printed substrate must be able to maintain its planarity on the mounter machine without increasing the total area of the entire substrate when it is assembled into a product.
It is an object of the present invention to provide a small electric substrate having positioning holes and which maintains the planarity of a flexible printed substrate when set in a mounter to mount parts.
To attain the above object, the present invention proposes an electric substrate (for example, flexible printed substrate) having positioning holes and on which electric parts are mounted, having a first area (a part mounting area) formed therein, a second area (part mounting area) formed therein, and a third area (a separable area) that joins the first and second areas like a xe2x80x9cbridgexe2x80x9d and that can be removed when the substrate is assembled into a predetermined equipment, the third area having a positioning hole (one of a set of positioning holes) for use in mounting electric parts on the substrate.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.